Substrate processing apparatus, substrate processing method, method of manufacturing semiconductor device, and non-transitory computer-readable recording medium

ABSTRACT

There is provided a technique capable of improving a uniformity of a substrate processing on a substrate surface. According to one aspect thereof, there is provided a substrate processing apparatus including: a substrate processing room; a plasma generation room; a gas supplier supplying a gas into the plasma generation room; a first coil surrounding the plasma generation room and to which an electric power is supplied; and a second coil surrounding the plasma generation room and to which an electric power is supplied. An axial direction of the second coil is equal to that of the first coil, a winding diameter of the second coil is different from that of the first coil, and a peak of a voltage distribution generated by supplying the electric power to the second coil does not overlap with a peak of a voltage distribution generated by the first coil.

CROSS REFERENCE TO RELATED APPLICATIONS

This non-provisional U.S. patent application is a continuation of U.S.patent application Ser. No. 17/692,722 filed on Mar. 11, 2022 and claimspriority under 35 U.S.C. § 119 of Japanese Patent Application No.2021-178348, filed on Oct. 29, 2021, in the Japanese Patent Office, theentire contents of which are hereby incorporated by reference.

TECHNICAL FIELD

The present disclosure relates to a substrate processing apparatus.

BACKGROUND

According to some related arts, a substrate processing apparatus capableof performing a substrate processing by exciting a process gas into aplasma state by supplying an electric power to two coils may be used.

For example, in the substrate processing apparatus described above, thetwo coils of the same diameter are arranged coaxially. Therefore, aplasma density may be biased in a direction parallel to a surface of thesubstrate, and a uniformity of the substrate processing on the surfaceof the substrate may decrease.

SUMMARY

According to the present disclosure, there is provided a techniquecapable of improving a uniformity of a substrate processing on a surfaceof a substrate.

According to one aspect of the technique of the present disclosure,there is provided a substrate processing apparatus including: a processchamber including: a plasma generation space capable of generating aplasma; and a substrate processing space capable of processing asubstrate; a gas supplier capable of supplying a gas into the plasmageneration space; a first coil provided to surround the plasmageneration space and configured to generate a first voltagedistribution; and a second coil provided to surround the plasmageneration space and configured to generate a second voltagedistribution such that a peak of the second voltage distribution doesnot overlap with a peak of the first voltage distribution.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram schematically illustrating a configuration of asubstrate processing apparatus preferably used in one or moreembodiments of the present disclosure.

FIG. 2 is a diagram schematically illustrating a first resonance coilused in a comparative example of the present disclosure.

FIG. 3 is a diagram schematically illustrating a relationship between acurrent and a voltage in the first resonance coil shown in FIG. 2 .

FIG. 4 is a diagram schematically illustrating an internal state of aprocess furnace when a process gas is excited into a plasma state usingthe first resonance coil shown in FIG. 2 .

FIG. 5 is a diagram schematically illustrating a horizontalcross-section of the process furnace at a central portion of the firstresonance coil shown in FIG. 4 in an axial direction.

FIG. 6 is a diagram schematically illustrating a second resonance coilpreferably used in the embodiments of the present disclosure.

FIG. 7 is a diagram schematically illustrating a relationship betweenthe current and the voltage in the first resonance coil and the secondresonance coil.

FIG. 8 is a diagram schematically illustrating an internal state of theprocess furnace when the process gas is excited into the plasma stateusing the first resonance coil and the second resonance coil shown inFIG. 7 .

FIG. 9 is a diagram schematically illustrating a horizontalcross-section of the process furnace at central portions of the firstresonance coil and the second resonance coil shown in FIG. 8 in theaxial direction.

FIG. 10 is a block diagram schematically illustrating a configuration ofa controller (which is a control structure) and related components ofthe substrate processing apparatus preferably used in the embodiments ofthe present disclosure.

FIG. 11 is a flow chart schematically illustrating a substrateprocessing preferably used in the embodiments of the present disclosure.

FIG. 12 is a diagram schematically illustrating an internal state of theprocess furnace when the process gas is excited into the plasma stateusing a modified example of a resonance coil preferably used in theembodiments of the present disclosure.

DETAILED DESCRIPTION Embodiments

Hereinafter, one or more embodiments (also simply referred to as“embodiments”) according to the technique of the present disclosure willbe described with reference to the drawings. The drawings used in thefollowing descriptions are all schematic. For example, a relationshipbetween dimensions of each component and a ratio of each component shownin the drawing may not always match the actual ones. Further, evenbetween the drawings, the relationship between the dimensions of eachcomponent and the ratio of each component may not always match.

(1) Configuration of Substrate Processing Apparatus

Hereinafter, a substrate processing apparatus 100 according to theembodiments of the present disclosure will be described with referenceto FIGS. 1 through 10 . For example, the substrate processing apparatus100 according to the present embodiments is configured to mainly performa substrate processing such as an oxidation process onto a film formedon a surface of a substrate or onto a base of the substrate.

Process Chamber

The substrate processing apparatus 100 includes a process furnace 202 inwhich a wafer 200 serving as the substrate is processed by a plasma. Theprocess furnace 202 includes a process vessel 203, and a process chamber201 is defined by the process vessel 203. The process vessel 203includes a dome-shaped upper vessel 210 serving as a first vessel and abowl-shaped lower vessel 211 serving as a second vessel. By covering thelower vessel 211 with the upper vessel 210, the process chamber 201 isdefined. The upper vessel 210 constitutes a plasma vessel in which aplasma generation space 201A is provided. In the plasma generation space201A, a process gas is excited into a plasma state.

In addition, a gate valve 244 is provided on a lower side wall of thelower vessel 211. While the gate valve 244 is open, the wafer 200 can betransferred (loaded) into the process chamber 201 through a substrateloading/unloading port 245 using a substrate transfer device (not shown)or be transferred (unloaded) out of the process chamber 201 through thesubstrate loading/unloading port 245 using the substrate transferdevice. While the gate valve 244 is closed, the gate valve 244 maintainsthe process chamber 201 airtight.

The process chamber 201 includes the plasma generation space 201A and asubstrate processing space 201B. The plasma generation space 201A is aspace in which a first resonance coil 212 and a second resonance coil214, which are coils serving as electrodes, are provided around thespace, and the plasma is generated in the plasma generation space 201A.More specifically, the plasma generation space 201A refers to a space inthe process chamber 201 above a lower end of the first resonance coil212 and below an upper end of the first resonance coil 212. Thesubstrate processing space 201B is a space that communicates with theplasma generation space 201A and in which the wafer 200 is processed.More specifically, the substrate processing space 201B refers to a spacein which the wafer 200 is processed by using the plasma, for example, aspace below the lower end of the first resonance coil 212. According tothe present embodiments, a diameter of the plasma generation space 201Ain a horizontal direction is the same as a diameter of the substrateprocessing space 201B in the horizontal direction. A configurationconstituting the plasma generation space 201A may also be referred to asa “plasma generation room”, and a configuration constituting thesubstrate processing space 201B may also be referred to as a “substrateprocessing room”. Further, the plasma generation space 201A may also bereferred to as a “plasma generation region” in the process chamber 201,and the substrate processing space 201B may also be referred to as a“substrate processing region” in the process chamber 201.

Susceptor

A susceptor (which is a substrate mounting table) 217 serving as asubstrate support on which the wafer 200 is placed is provided at acenter of a bottom portion of the process chamber 201. The susceptor 217is provided in the process chamber 201 and below the first resonancecoil 212.

A heater 217B serving as a heating structure is integrally embedded inthe susceptor 217. When an electric power is supplied to the heater217B, the heater 217B is configured to heat the wafer 200.

The susceptor 217 is electrically insulated from the lower vessel 211.An impedance adjusting electrode 217C is provided in the susceptor 217in order to further improve a uniformity of a density of the plasmagenerated on the wafer 200 placed on the susceptor 217. The impedanceadjustment electrode 217C is grounded via a variable impedance regulator275 serving as an impedance adjusting structure.

A susceptor elevator 268 including a driving structure capable ofelevating and lowering the susceptor 217 is provided at the susceptor217. Through-holes 217A are provided at the susceptor 217, and waferlift pins 266 are provided on a bottom surface of the lower vessel 211.When the susceptor 217 is lowered by the susceptor elevator 268, thewafer lift pins 266 are configured to penetrate the through-holes 217Awithout contacting the susceptor 217.

Gas Supplier

A gas supply head 236 is provided above the process chamber 201, thatis, on an upper portion of the upper vessel 210. The gas supply head 236includes a cap-shaped lid 233, a gas inlet port 234, a buffer chamber237, an opening 238, a shield plate 240 and a gas outlet port 239. Thegas supply head 236 is configured such that a gas such as a reactive gasis supplied into the process chamber 201 through the gas supply head236. The buffer chamber 237 functions as a dispersion space in which thegas such as the reactive gas introduced (supplied) through the gas inletport 234 is dispersed.

A downstream end of an oxygen-containing gas supply pipe 232A throughwhich an oxygen-containing gas is supplied, a downstream end of ahydrogen-containing gas supply pipe 232B through which ahydrogen-containing gas is supplied and a downstream end of an inert gassupply pipe 232C through which an inert gas is supplied are connected tothe gas inlet port 234 through a confluence pipe 232. Hereinafter, theoxygen-containing gas supply pipe 232A may also be simply referred to asa “gas supply pipe 232A”, the hydrogen-containing gas supply pipe 232Bmay also be simply referred to as a “gas supply pipe 232B”, and theinert gas supply pipe 232C may also be simply referred to as a “gassupply pipe 232C”. An oxygen-containing gas supply source 250A, a massflow controller (MFC) 252A serving as a flow rate controller and a valve253A serving as an opening/closing valve are sequentially provided atthe oxygen-containing gas supply pipe 232A in this order from anupstream side to a downstream side of the oxygen-containing gas supplypipe 232A in a gas flow direction. A hydrogen-containing gas supplysource 250B, an MFC 252B and a valve 253B are sequentially provided atthe hydrogen-containing gas supply pipe 232B in this order from anupstream side to a downstream side of the hydrogen-containing gas supplypipe 232B in the gas flow direction. An inert gas supply source 250C, anMFC 252C and a valve 253C are sequentially provided at the inert gassupply pipe 232C in this order from an upstream side to a downstreamside of the inert gas supply pipe 232C in the gas flow direction. Avalve 243A is provided on a downstream side of the confluence pipe 232where the oxygen-containing gas supply pipe 232A, thehydrogen-containing gas supply pipe 232B and the inert gas supply pipe232C join. The confluence pipe 232 is connected to an upstream end thegas inlet port 234. It is possible to supply the process gas such as theoxygen-containing gas, the hydrogen-containing gas and the inert gasinto the process chamber 201 via the oxygen-containing gas supply pipe232A, the hydrogen-containing gas supply pipe 232B and the inert gassupply pipe 232C by opening and closing the valves 253A, 253B, 253C and243A while adjusting flow rates of the respective gases by the MFCs252A, 252B and 252C.

For example, an oxygen-containing gas supplier (which is anoxygen-containing gas supply structure or an oxygen-containing gassupply system) according to the present embodiments is constitutedmainly by the oxygen-containing gas supply pipe 232A, the MFC 252A, thevalve 253A and the valve 243A. In addition, a hydrogen-containing gassupplier (which is a hydrogen-containing gas supply structure or ahydrogen-containing gas supply system) according to the presentembodiments is constituted mainly by the hydrogen-containing gas supplypipe 232B, the MFC 252B, the valve 253B and the valve 243A. In addition,an inert gas supplier (which is an inert gas supply structure or aninert gas supply system) according to the present embodiments isconstituted mainly by the inert gas supply pipe 232C, the MFC 252C, thevalve 253C and the valve 243A.

A gas supplier (which is a gas supply structure or a gas supply system)according to the present embodiments is constituted mainly by theoxygen-containing gas supply pipe 232A, the hydrogen-containing gassupply pipe 232B, the inert gas supply pipe 232C, the MFCs 252A, 252Band 252C, the valves 253A, 253B and 253C and the valve 243A. The gassupplier (gas supply system) is configured such that the process gas canbe supplied into the process vessel 203. For example, one of theoxygen-containing gas supplier, the hydrogen-containing gas supplier andthe inert gas supplier or a combination thereof may also be referred toas the “gas supplier”.

Exhauster

A gas exhaust port 235 is provided on a side wall of the lower vessel211. An inner atmosphere of the process chamber 201 (for example, thereactive gas in the process chamber 201) is exhausted through the gasexhaust port 235. An upstream end of a gas exhaust pipe 231 is connectedto the gas exhaust port 235. An APC (Automatic Pressure Controller)valve 242 serving as a pressure regulator (pressure adjustingstructure), a valve 243B serving as an opening/closing valve and avacuum pump 246 serving as a vacuum exhaust apparatus are sequentiallyprovided at the gas exhaust pipe 231 in this order from an upstream sideto a downstream side of the gas exhaust pipe 231 in the gas flowdirection. An exhauster (which is an exhaust structure or an exhaustsystem) according to the present embodiments is constituted mainly bythe gas exhaust port 235, the gas exhaust pipe 231, the APC valve 242and the valve 243B. The exhauster may further include the vacuum pump246.

Plasma Generator

The first resonance coil 212 and the second resonance coil 214 arerespectively arranged on an outer side of the process vessel 203 so asto surround an outer periphery of the process vessel 203. Specifically,the first resonance coil 212 and the second resonance coil 214 arerespectively arranged so as to surround an outer periphery of a portion(region) corresponding to the plasma generation space 201A (that is, anouter periphery of the plasma generation room) in the process vessel203. The first resonance coil 212 is provided by winding a conductor212A of a line shape or a string shape a plurality of times in a spiralshape in the same direction. Both ends (that is, an upper end 212B and alower end 212C shown in FIG. 8 ) of the first resonance coil 212 aregrounded, and a portion of the first resonance coil 212 between theupper end 212B and the lower end 212C surrounds the outer periphery ofthe process vessel 203. Specifically, the first resonance coil 212surrounds an outer peripheral portion of the process chamber 201, thatis, an outer periphery of a side wall of the upper vessel 210. In otherwords, the process vessel 203 is inserted into an inner side of thefirst resonance coil 212. In addition, according to the presentembodiments, the first resonance coil 212 and the outer periphery (outersurface) of the process vessel 203 are provided close to each other suchthat a high frequency electromagnetic field generated by the firstresonance coil 212 can excite the process gas in the process vessel 203into the plasma state by the plasma. Further, a winding diameter of thefirst resonance coil 212 according to the present embodiments isconstant and the same at positions on the first resonance coil 212. AnRF power is supplied to the first resonance coil 212.

The second resonance coil 214 is provided by winding a conductor 214A ofa line shape or a string shape a plurality of times in a spiral shape inthe same direction. Both ends (that is, an upper end 214B and a lowerend 214C shown in FIG. 8 ) of the second resonance coil 214 aregrounded, and a portion of the second resonance coil 214 between theupper end 214B and the lower end 214C surrounds the outer periphery ofthe process vessel 203. Specifically, the second resonance coil 214surrounds the outer peripheral portion of the process chamber 201, thatis, the outer periphery of the side wall of the upper vessel 210. Inother words, the process vessel 203 is inserted into an inner side ofthe second resonance coil 214. In addition, according to the presentembodiments, similar to the first resonance coil 212, the secondresonance coil 214 and the outer periphery (outer surface) of theprocess vessel 203 are provided close to each other such that a highfrequency electromagnetic field generated by the second resonance coil214 can excite the process gas in the process vessel 203 into the plasmastate by the plasma. Further, a winding diameter of the second resonancecoil 214 according to the present embodiments is constant and the sameat positions on the second resonance coil 214. Further, according to thepresent embodiments, the winding diameter D1 of the first resonance coil212 and the winding diameter D2 of the second resonance coil 214 aredifferent. Specifically, the winding diameter D2 of the second resonancecoil 214 is set to be greater than the winding diameter D1 of the firstresonance coil 212. According to the present embodiments, for example,the winding diameter D2 is preferably set within a range from 101% to125%, preferably from 105% to 120% of the winding diameter D1.

As shown in FIG. 8 , an axial direction of the first resonance coil 212(that is, a direction along a spiral axis of the first resonance coil212) and an axial direction of the second resonance coil 214 (that is, adirection along a spiral axis of the second resonance coil 214) are thesame direction. That is, the axial direction of the second resonancecoil 214 is equal to the axial direction of the first resonance coil212. More specifically, according to the present embodiments, the spiralaxis of the first resonance coil 212 and the spiral axis of the secondresonance coil 214 are coaxial. In addition, according to the presentembodiments, the axial direction of each resonance coil is the samedirection as an up-and-down direction of the substrate processingapparatus 100, that is, the same direction as a vertical direction. InFIG. 7 , an upper direction of the substrate processing apparatus 100 isindicated by an arrow “U”, and a radial direction of the process vessel203 is indicated by an arrow “R”. According to the present embodiments,the radial direction of the process vessel 203 is the same direction asa horizontal direction of the substrate processing apparatus 100, and isalso the same direction as a direction perpendicular to the spiral axisof each resonance coil. Further, the conductor 212A constituting thefirst resonance coil 212 and the conductor 214A constituting the secondresonance coil 214 are alternately arranged in the vertical direction(that is, the axial direction of each resonance coil). According to thepresent embodiments, for example, when the first resonance coil 212 andthe second resonance coil 214 are viewed from the vertical direction, anouter peripheral portion of the first resonance coil 212 overlaps withan inner peripheral portion of the second resonance coil 214. Byproviding the first resonance coil 212 and the second resonance coil 214such that a part of the first resonance coil 212 overlaps with a part ofthe second resonance coil 214 when viewed from the vertical direction,it is possible to suppress an increase in a size of a vessel (not shown)covering each resonance coil in the radial direction. On the other hand,for example, when the first resonance coil 212 and the second resonancecoil 214 do not overlap with each other when viewed from the verticaldirection, that is, when there is a gap between the first resonance coil212 and the second resonance coil 214, by securing a distance betweenthe first resonance coil 212 and the second resonance coil 214, it ispossible to suppress a generation of an arc discharge. Further, thedistance between the first resonance coil 212 and the second resonancecoil 214 may be set to a distance in advance such that no arc dischargeis generated therebetween. In addition, the RF power is supplied to thesecond resonance coil 214.

As shown in FIG. 8 , an axial length (that is, a length along the spiralaxis) of a coil portion of the first resonance coil 212 is set to belonger than an axial length (that is, a length along the spiral axis) ofa coil portion of the second resonance coil 214. Therefore, theconductor 212A of the first resonance coil 212 and the conductor 214A ofthe second resonance coil 214 are alternately arranged in the verticaldirection (that is, the axial direction of each resonance coil) from anupper portion to the vicinity of a central portion of the firstresonance coil 212 in the vertical direction. According to the presentembodiments, a region in which the first resonance coil 212 and thesecond resonance coil 214 are arranged is provided on the outerperiphery of the process vessel 203. Specifically, the region in whichthe first resonance coil 212 and the second resonance coil 214 arearranged may also be referred to as a “first arrangement region”, and isindicated by a reference character “FA” (see FIG. 8 ). In addition, aregion in which the first resonance coil 212 is arranged and the secondresonance coil 214 is not arranged may be referred to as a “secondarrangement region”, and is indicated by a reference character “SA” (seeFIG. 8 ). The second arrangement region SA is provided closer to thesusceptor 217 than the first arrangement region FA in the up-and-downdirection of the substrate processing apparatus 100 (that is, thevertical direction).

An RF (Radio Frequency) sensor 272, an RF power supply 273 and a matcher(which is a matching structure) 274 configured to perform an impedancematching or an output frequency matching for the RF power supply 273 areconnected to the first resonance coil 212.

The RF power supply 273 is configured to supply the RF power to thefirst resonance coil 212. The RF sensor 272 is provided at an outputside of the RF power supply 273. The RF sensor 272 is configured tomonitor information of the traveling wave or reflected wave of the RFpower supplied from the RF power supply 273. The information of thereflected wave monitored by the RF sensor 272 is input to the matcher274, and the matcher 274 is configured to match (or adjust) an impedanceor a frequency of the RF power output from the RF power supply 273 so asto minimize the reflected wave based on the information of the reflectedwave input from the RF sensor 272.

The RF power supply 273 includes a power supply controller (which is acontrol circuit) (not shown) and an amplifier (which is an outputcircuit) (not shown). The power supply controller includes a highfrequency oscillation circuit (not shown) and a preamplifier (not shown)in order to adjust an oscillation frequency and an output. The amplifieramplifies the output to a predetermined output level. The power supplycontroller controls the amplifier based on output conditions relating tothe frequency and the power, which are set in advance through anoperation panel (not shown), and the amplifier supplies a constant RFpower to the first resonance coil 212 via a transmission line. The RFsensor 272 and the matcher 274 are collectively referred to as a “RFpower supplier 271” which is a RF power supply structure or a RF powersupply system. The RF power supplier 271 may further include the RFpower supply 273.

An RF (Radio Frequency) sensor 282, a RF power supply 283 and a matcher(which is a matching structure) 284 configured to perform an impedancematching or an output frequency matching for the RF power supply 283 areconnected to the second resonance coil 214.

The RF power supply 283 is configured to supply the RF power to thesecond resonance coil 214. The RF sensor 282 is provided at an outputside of the RF power supply 283. The RF sensor 282 is configured tomonitor information of the traveling wave or reflected wave of the RFpower supplied from the RF power supply 283. The information of thereflected wave monitored by the RF sensor 282 is input to the matcher284, and the matcher 284 is configured to match (or adjust) an impedanceor a frequency of the RF power output from the RF power supply 283 so asto minimize the reflected wave based on the information of the reflectedwave input from the RF sensor 282.

The RF power supply 283 includes a power supply controller (which is acontrol circuit) (not shown) and an amplifier (which is an outputcircuit) (not shown). The power supply controller includes a highfrequency oscillation circuit (not shown) and a preamplifier (not shown)in order to adjust an oscillation frequency and an output. The amplifieramplifies the output to a predetermined output level. The power supplycontroller controls the amplifier based on output conditions relating tothe frequency and the power, which are set in advance through theoperation panel (not shown), and the amplifier supplies a constant RFpower to the second resonance coil 214 via a transmission line. The RFsensor 282 and the matcher 284 are collectively referred to as a “RFpower supplier 281” which is a RF power supply structure or an RF powersupply system. The RF power supplier 281 may further include the RFpower supply 283.

The winding diameter, a winding pitch and the number of winding turns ofthe first resonance coil 212 are set such that the first resonance coil212 resonates at a constant wavelength to form a standing wave of apredetermined wavelength. That is, an electrical length of the firstresonance coil 212 is set to an integral multiple (n times, where n isequal to or greater than 1) of a wavelength of a predetermined frequencyof the RF power supplied from the RF power supply 273.

In addition, the winding diameter, a winding pitch and the number ofwinding turns of the second resonance coil 214 are set such that thesecond resonance coil 214 resonates at a constant wavelength to form astanding wave of a predetermined wavelength. That is, an electricallength of the second resonance coil 214 is set to an integral multiple(n times, where n is equal to or greater than 1) of a wavelength of apredetermined frequency of the RF power supplied from the RF powersupply 283.

Specifically, considering conditions such as the power to be applied, astrength of a magnetic field to be generated and a shape of thesubstrate processing apparatus 100 to be applied, the first resonancecoil 212 is set such that, for example, the magnetic field of about 0.01Gauss to about 10 Gauss can be generated by the RF power whose frequencyis from 800 kHz to 50 MHz and whose power is from 0.1 kW to 5 kW. Forexample, the first resonance coil 212 whose effective cross-section isfrom 50 mm2 to 300 mm2 and whose diameter is from 200 mm to 500 mm iswound, for example, twice to 60 times around an outer circumferentialside of the process chamber 201 defining the plasma generation space201A. Similarly, considering conditions such as the power to be applied,a strength of a magnetic field to be generated and a shape of thesubstrate processing apparatus 100 to be applied, the second resonancecoil 214 is set such that, for example, the magnetic field of about 0.01Gauss to about 10 Gauss can be generated by the RF power whose frequencyis from 800 kHz to 50 MHz and whose power is from 0.1 kW to 5 kW. Forexample, the second resonance coil 214 whose effective cross-section isfrom 50 mm2 to 300 mm2 and whose diameter is from 200 mm to 500 mm iswound, for example, twice to 60 times around the outer circumferentialside of the process chamber 201 defining the plasma generation space201A.

As shown in FIG. 7 , the first resonance coil 212 and the secondresonance coil 214 are arranged such that a position of an anti-node ofthe standing wave by the first resonance coil 212 and a position of ananti-node of the standing wave by the second resonance coil 214 do notoverlap with each other. In other words, a peak of a voltagedistribution of the first resonance coil 212 and a peak of a voltagedistribution of the second resonance coil 214 do not overlap with eachother. Further, the distance between the first resonance coil 212 andthe second resonance coil 214 is set to the distance at which no arcdischarge is generated between the conductor 212A of the first resonancecoil 212 and the conductor 214A of the second resonance coil 214.

For example, a copper pipe, a copper thin plate, an aluminum pipe, analuminum thin plate and a material obtained by depositing copper oraluminum on a polymer belt may be used as a material constituting eachof the first resonance coil 212 and the second resonance coil 214. Eachof the first resonance coil 212 and the second resonance coil 214 issupported by a plurality of supports (not shown) of a plate shape andmade of an insulating material, which are provided on an upper endsurface of a base plate 248 so as to extend vertically.

The both ends of the first resonance coil 212 are electrically grounded.One end of the first resonance coil 212 (for example, the upper end 212Bshown in FIGS. 2, 4 and 8 ) is grounded via a movable tap 300 in orderto fine-tune the electrical length of the first resonance coil 212 whenthe substrate processing apparatus 100 is newly installed or processconditions of the substrate processing apparatus 100 are changed, andthe other end of the first resonance coil 212 (for example, the lowerend 212C shown in FIGS. 1 through 4, 7 and 8 ) is grounded as a fixedground. In addition, in order to fine-tune impedance (or the electricallength) of the first resonance coil 212 when the substrate processingapparatus 100 is newly installed or the process conditions of thesubstrate processing apparatus 100 are changed, a power feeder (notshown) is constituted by a movable tap 305 between the grounded ends ofthe first resonance coil 212. Further, a position of the movable tap 305may be adjusted in order for the resonance characteristics of the firstresonance coil 212 to become approximately the same as those of the RFpower supply 273. Since the first resonance coil 212 includes a variableground structure (that is, the movable tap 300) and a variable powersupply feeding structure (that is, the power feeder constituted by themovable tap 305), it is possible to easily adjust a resonance frequencyand a load impedance of the process chamber 201. The upper end 212B ofthe first resonance coil 212 according to the present embodiments is anexample of a first ground connection portion according to the techniqueof the present disclosure. Further, the lower end 212C of the firstresonance coil 212 according to the present embodiments is an example ofa second ground connection portion according to the technique of thepresent disclosure. When the vicinity of the upper end 212B of the firstresonance coil 212 is grounded, a location in the vicinity of the upperend 212B becomes a grounding point and serves as the first groundconnection portion. In addition, when the vicinity of the lower end 212Cof the first resonance coil 212 is grounded, a location in the vicinityof the lower end 212C becomes a grounding point and serves as the secondground connection portion.

The both ends of the second resonance coil 214 are electricallygrounded. One end of the second resonance coil 214 (for example, theupper end 214B shown in FIGS. 6 and 8 ) is grounded via a movable tap302 in order to fine-tune the electrical length of the second resonancecoil 214 when the substrate processing apparatus 100 is newly installedor the process conditions of the substrate processing apparatus 100 arechanged, and the other end of the second resonance coil 214 (forexample, the lower end 214C shown in FIGS. 1, 6, 7 and 8 ) is groundedas a fixed ground. In addition, in order to fine-tune the impedance (orthe electrical length) of the second resonance coil 214 when thesubstrate processing apparatus 100 is newly installed or the processconditions of the substrate processing apparatus 100 are changed, apower feeder (not shown) is constituted by a movable tap 306 between thegrounded ends of the second resonance coil 214. Further, a position ofthe movable tap 306 may be adjusted in order for the resonancecharacteristics of the second resonance coil 214 to become approximatelythe same as those of the RF power supply 283. Since the second resonancecoil 214 includes a variable ground structure (that is, the movable tap302) and a variable power supply feeding structure (that is, the powerfeeder constituted by the movable tap 306), it is possible to easilyadjust the resonance frequency and the load impedance of the processchamber 201. The upper end 214B of the second resonance coil 214according to the present embodiments is an example of a third groundconnection portion according to the technique of the present disclosure.Further, the lower end 214C of the second resonance coil 214 accordingto the present embodiments is an example of a fourth ground connectionportion according to the technique of the present disclosure. When thevicinity of the upper end 214B of the second resonance coil 214 isgrounded, a location in the vicinity of the upper end 214B becomes agrounding point and serves as the third ground connection portion. Inaddition, when the vicinity of the lower end 214C of the secondresonance coil 214 is grounded, a location in the vicinity of the lowerend 214C becomes a grounding point and serves as the fourth groundconnection portion.

A waveform adjustment circuit 308 constituted by a resonance coil (notshown) and a shield (not shown) is inserted into one end (or the otherend or the both ends) of the first resonance coil 212 so that the phasecurrent and the opposite phase current flow symmetrically with respectto an electrical midpoint of the first resonance coil 212. The waveformadjustment circuit 308 is configured to be open by setting the firstresonance coil 212 to an electrically disconnected state or anelectrically equivalent state. In addition, an end portion of the firstresonance coil 212 may be non-grounded by a choke series resistor, ormay be DC-connected to a fixed reference potential.

In addition, a waveform adjustment circuit 309 constituted by aresonance coil (not shown) and a shield (not shown) is inserted into oneend (or the other end or the both ends) of the second resonance coil 214so that the phase current and the opposite phase current flowsymmetrically with respect to an electrical midpoint of the secondresonance coil 214. The waveform adjustment circuit 309 is configured tobe open by setting the second resonance coil 214 to an electricallydisconnected state or an electrically equivalent state. In addition, anend portion of the second resonance coil 214 may be non-grounded by achoke series resistor, or may be DC-connected to a fixed referencepotential.

For example, the waveform adjustment circuit 308 or 309 may be arrangedon at least one of the first resonance coil 212 or the second resonancecoil 214. According to the present embodiments, as the waveformadjustment circuit 308 or 309, for example, a variable capacitor may beused, or a wire (coil) made of a conductor may be used.

A shield plate 223 is provided to shield an electric field outside ofthe first resonance coil 212 and/or the second resonance coil 214 and toform a capacitive component (also referred to as a “C component”) of thefirst resonance coil 212 or the second resonance coil 214 appropriatefor constructing a resonance circuit between the shield plate 223 andthe first resonance coil 212 or between the shield plate 223 and thesecond resonance coil 214. In general, the shield plate 223 is made of aconductive material such as an aluminum alloy, and is of a cylindricalshape. The shield plate 223 is disposed, for example, about 5 mm to 150mm apart from an outer periphery of each of the first resonance coil 212and the second resonance coil 214.

A first plasma generator according to the present embodiments isconstituted mainly by the first resonance coil 212, the RF sensor 272and the matcher 274. In addition, the first plasma generator may furtherinclude the RF power supply 273. Further, a second plasma generatoraccording to the present embodiments is constituted mainly by the secondresonance coil 214, the RF sensor 282 and the matcher 284. In addition,the second plasma generator may further include the RF power supply 283.The first plasma generator and the second plasma generator may becollectively referred to as a “plasma generator”.

Hereinafter, a principle of generating the plasma in the substrateprocessing apparatus 100 of the present embodiments and the propertiesof the generated plasma will be described. Since the principles ofgenerating the plasma by each of the first resonance coil 212 and thesecond resonance coil 214 are the same, the principle of generating theplasma by the first resonance coil 212 will be described hereafter as anexample (see FIGS. 3 through 5 ).

A plasma generation circuit constituted by the first resonance coil 212is configured as an RLC parallel resonance circuit. When the wavelengthof the RF power supplied from the RF power supply 273 and the electricallength of the first resonance coil 212 are the same, the resonancecondition of the first resonance coil 212 is that a reactance componentgenerated by a capacitance component or an inductive component of thefirst resonance coil 212 is canceled out to become a pure resistance.However, when the plasma is generated in the plasma generation circuitdescribed above, an actual resonance frequency may fluctuate slightlydepending on conditions such as a variation (change) in a capacitivecoupling between a voltage portion of the first resonance coil 212 andthe plasma, a variation in an inductive coupling between the plasmageneration space 201A and the plasma and an excitation state of theplasma.

Therefore, in the substrate processing apparatus 100 according to thepresent embodiments, in order to compensate for a resonance shift in thefirst resonance coil 212 when the plasma is generated by adjusting thepower supplied from the RF power supply 273, the RF sensor 272 isconfigured to detect the power of the reflected wave from the firstresonance coil 212 when the plasma is generated, and the matcher 274 isconfigured to correct the output of the RF power supply 273 based on thedetected power of the reflected wave.

Specifically, the matcher 274 is configured to increase or decrease theimpedance or the output frequency of the RF power supply 273 such thatthe power of the reflected wave is minimized based on the power of thereflected wave from the first resonance coil 212 detected by the RFsensor 272 when the plasma is generated. In case the impedance iscontrolled by the matcher 274, the matcher 274 is constituted by avariable capacitor control circuit (not shown) capable of correcting apreset impedance. In case the output frequency of the RF power supply273 is controlled by the matcher 274, the matcher 274 is constituted bya frequency control circuit (not shown) capable of correcting a presetoscillation frequency of the RF power supply 273. For example, the RFpower supply 273 and the matcher 274 may be provided integrally as asingle body.

According to the configuration related to the first resonance coil 212according to the present embodiments, the RF power whose frequency isequal to the actual resonance frequency of the first resonance coil 212combined with the plasma is supplied to the first resonance coil 212 (orthe RF power is supplied to match an actual impedance of the firstresonance coil 212 combined with the plasma). Therefore, the standingwave in which the phase voltage thereof and the opposite phase voltagethereof are always canceled out by each other is generated in the firstresonance coil 212 (see FIG. 3 ). For example, when the wavelength ofthe RF power and the electrical length of the first resonance coil 212are the same, the highest phase current is generated at an electricalmidpoint of the first resonance coil 212 (node with zero voltage).Specifically, when the RF power is supplied from the RF power supply 273to the first resonance coil 212, for example, a current standing waveand a voltage standing wave whose wavelengths are equal to thewavelength of the RF power supplied from the RF power supply 273 aregenerated between both ends of a line of the first resonance coil 212.Among waveforms on a right portion of FIG. 3 , a broken line illustratesthe current and a solid line illustrates the voltage. As shown by thewaveform on the right portion of FIG. 3 , an amplitude of the currentstanding wave is maximized at the both ends of the first resonance coil212 and a midpoint (that is, the electrical midpoint) of the firstresonance coil 212. Therefore, a donut-shaped induction plasma (which isan inductively coupled plasma (ICP)) 310 of an extremely low electricpotential is generated in the vicinity of the electrical midpoint of thefirst resonance coil 212. The donut-shaped ICP 310 is hardlycapacitively coupled with walls of the process chamber 201 or thesusceptor 217. Specifically, a high frequency magnetic field isgenerated in the vicinity of the electrical midpoint of the firstresonance coil 212 where the amplitude of the current standing wave ismaximized, and a plasma discharge of the process gas supplied into theplasma generation space 201A in the upper vessel 210 is generated by ahigh frequency electromagnetic field induced by the high frequencymagnetic field. The plasma of the process gas is generated in thevicinity of the electrical midpoint of the first resonance coil 212 byexciting the process gas discharged by the high frequencyelectromagnetic field. Hereinafter, the plasma of the process gasgenerated by the high frequency electromagnetic field generated in thevicinity of a location (region) where the amplitude of the current isgreat as described above may also be referred to as the “ICP”. As shownin FIG. 4 , the ICP is generated in a donut shape in a region in thevicinity of the electrical midpoint of the first resonance coil 212 in aspace along an inner wall surface of the upper vessel 210. Thereby, theICP whose plasma density is uniform in a direction parallel to a surfaceof the wafer 200 can be generated. Similarly, the induction plasma isalso generated at the both axial ends of the first resonance coil 212according to the same principle.

Subsequently, an internal state of the process furnace 202 when theplasma is generated using the first resonance coil 212 and the secondresonance coil 214 will be described.

In the substrate processing apparatus 100 according to the presentembodiments shown in FIG. 8 , the first resonance coil 212 and thesecond resonance coil 214 are respectively provided around the plasmageneration space 201A, similar to a case where the first resonance coil212 alone is provided as shown in FIG. 4 . For example, when the RFpower is supplied to the first resonance coil 212 while the process gasis supplied to the plasma generation space 201A, the voltage and thecurrent are generated as shown on a right portion of FIG. 7 by theprinciple described above, and the ICP 310 is generated in the plasmageneration space 201A as shown in FIG. 8 .

Similarly, when the RF power is supplied to the second resonance coil214 while the process gas is supplied to the plasma generation space201A, the voltage and the current are generated as shown on a leftportion of FIG. 7 by the principle described above, and an ICP 312 isgenerated in the plasma generation space 201A as shown in FIG. 8 .

By using a plurality of resonance coils (for example, the firstresonance coil 212 and the second resonance coil 214), it is possible togenerate a large amount of the plasma as compared with a case where asingle resonance coil (for example, the first resonance coil 212 alone)is used to generate the plasma. That is, it is possible to generate alarge amount of radical components in the plasma.

According to the present embodiments, the winding diameter D2 of thesecond resonance coil 214 is set to be different from the windingdiameter D1 of the first resonance coil 212. Therefore, as shown in FIG.7 , the peak of the voltage distribution of the first resonance coil 212and the peak of the voltage distribution of the second resonance coil214 are displaced with each other in the radial direction. That is, thepeak of the voltage distribution of the first resonance coil 212 and thepeak of the voltage distribution of the second resonance coil 214 do notoverlap with each other. By making the peaks of the voltagedistributions of the two resonance coils (that is, the first resonancecoil 212 and the second resonance coil 214) to be apart from each otheras described above, it is possible to uniformize a density of the highlyconcentrated induction plasma along the radial direction (see FIG. 9 ).Thereby, it is possible to realize a uniformity of the density ofinduction plasma on a surface of the substrate (that is, on the surfaceof the wafer 200).

Further, the second resonance coil 214 according to the presentembodiments is configured such that, in the direction (horizontaldirection) perpendicular to the axial direction, the peak of the voltagedistribution thereof does not overlap with the peak of the voltagedistribution of the first resonance coil 212. By making the peaks of thevoltage distributions of the two resonance coils in the horizontaldirection to be apart from each other as described above, it is possibleto uniformize the density of the plasma. For example, as shown in FIG. 9, by separately forming the ICPs (that is, the ICP 310 and the ICP 312)using the two resonance coils, it is possible to increase an amount ofthe plasma in the radial direction.

Further, the second resonance coil 214 according to the presentembodiments is configured such that, in the axial direction (verticaldirection), the peak of the voltage distribution thereof does notoverlap with the peak of the voltage distribution of the first resonancecoil 212. By making the peaks of the voltage distributions of the tworesonance coils in the vertical direction to be apart from each other asdescribed above, it is possible to supplement a state of one inductionplasma by the other induction plasma. Therefore, it is possible toextend a lifetime of the entirety of the induction plasma.

Further, according to the present embodiments, the first arrangementregion FA and the second arrangement region SA are provided on the outerperiphery of the process vessel 203. In addition, the first resonancecoil 212 alone is continuously arranged in the second arrangement regionSA. Therefore, it is possible to adjust a physical length of a coillength with respect to the plasma generation space 201A. Thereby, it ispossible to secure a flexibility in the design.

Further, according to the present embodiments, the winding diameter D1of the first resonance coil 212 is set to be smaller than the windingdiameter D2 of the second resonance coil 214. It is possible to form thepeak of the voltage distribution using the first resonance coil 212 withthe winding diameter D1 smaller than the winding diameter D2 of thesecond resonance coil 214. Thereby, it is possible to supply theinduction plasma whose density is high to a central region of thesubstrate (that is, the wafer 200).

Further, the second arrangement region SA according to the presentembodiments is provided closer to the susceptor 217 on which the wafer200 is placed in the process vessel 203 than the first arrangementregion FA in the axial direction (vertical direction). According to thepresent embodiments, for example, by reducing the winding diameter ofthe resonance coil provided closer to the susceptor 217 (that is, byreducing the winding diameter D1 of the first resonance coil 212), it ispossible to easily supply the plasma to the central region of the wafer200 directly below the resonance coil provided closer to the susceptor217.

Further, the process vessel 203 according to the present embodiments isprovided with the exhauster capable of exhausting the process gas fromthe outer periphery of the susceptor 217. As a result, it is possible todiffuse a flow of the induction plasma supplied to the central region ofthe wafer 200 toward the outer periphery of the susceptor 217. That is,it is possible to diffuse the plasma whose density is high supplied tothe central region of the wafer 200 in an outer peripheral direction,and therefore, it is possible to uniformize a processing of the wafer200 on the surface of the wafer 200.

Further, according to the present embodiments, in the first arrangementregion FA, the conductor 212A of the first resonance coil 212 and theconductor 214A of the second resonance coil 214 are separated from eachother at the distance such that no arc discharge is generatedtherebetween. Further, in the second arrangement region SA, theconductor 212A of the first resonance coil 212 is provided such that noarc discharge is generated between portions of the conductor 212Awounded the plurality of times with a gap. For example, when a voltagedifference between the resonance coils is equal to or greater than athreshold value, the arc discharge may be generated therebetween, andthereby, the electric power may leak. When the electric power leaks, adesired induction plasma cannot be provided. On the other hand,according to the present embodiments, the conductor 212A and theconductor 214A are separated from each other at the distance such thatno arc discharge is generated therebetween. Thereby, it is possible tosuppress a leakage of the electric power. As a result, it is possible toprovide the desired induction plasma.

Further, the first resonance coil 212 according to the presentembodiments is configured such that the electrical length between theboth ends thereof grounded is a multiple of the wavelength of the RFpower supplied to the first resonance coil 212. By grounding the bothends of the first resonance coil 212 as described above, it is possibleto provide the multiple of the wavelength of the RF power supplied tothe first resonance coil 212. Thereby, it is possible to provide a sinecurve of the voltage shown in FIG. 7 . As a result, it is possible toeasily control the peak of the voltage distribution of the firstresonance coil 212.

Further, the second resonance coil 214 according to the presentembodiments is configured such that the electrical length between theboth ends thereof grounded is a multiple of the wavelength of the RFpower supplied to the second resonance coil 214. By grounding the bothends of the second resonance coil 214 as described above, it is possibleto provide the multiple of the wavelength of the RF power supplied tothe second resonance coil 214. Thereby, it is possible to provide a sinecurve of the voltage shown in FIG. 7 . As a result, it is possible toeasily control the peak of the voltage distribution of the secondresonance coil 214.

Further, according to the present embodiments, the waveform adjustmentcircuits 308 and 309 configured to correct the electrical length areconnected to the first resonance coil 212 and the second resonance coil214, respectively, such that the electrical length of the firstresonance coil 212 and the electrical length of the second resonancecoil 214 are equal to each other. When the electrical lengths describedabove cannot be adjusted by grounding, the electrical lengths can beadjusted by using the waveform adjustment circuits 308 and 309 asdescribed above.

Further, according to the present embodiments, a position of thegrounded upper end 212B of the first resonance coil 212 in the verticaldirection is set to be different from a position of the grounded upperend 214B of the second resonance coil 214. By setting grounding heightsof the upper ends of the resonance coils different from each other asdescribed above, it is possible to more reliably make positions of thepeaks of the voltage distributions to be more reliably spaced apart fromeach other.

Further, according to the present embodiments, a position of thegrounded lower end 212C of the first resonance coil 212 in the verticaldirection is set to be different from a position of the grounded lowerend 214C of the second resonance coil 214. By setting grounding heightsof the lower ends of the resonance coils different from each other asdescribed above, it is possible to more reliably make the positions ofthe peaks of the voltage distributions to be more reliably spaced apartfrom each other.

Further, according to the present embodiments, the frequency of the RFpower generated from the RF power supply 273 connected to the firstresonance coil 212 is the same as the frequency of the RF powergenerated from the RF power supply 283 connected to the second resonancecoil 214. When the frequencies of the RF power supply 273 and the RFpower supply 283 are the same as described above, it is possible to setthe wavelengths of the RF power supply 273 and the RF power supply 283to be the same. As a result, it is possible to easily control thepositions of the peaks of the voltage distributions.

Further, according to the present embodiments, a controller 221described later controls components constituting the substrateprocessing apparatus 100 to supply the process gas into the processchamber 201 while supplying the RF power to the first resonance coil 212and the second resonance coil 214. Thereby, it is possible to generatetwo types of the induction plasma in the plasma generation space 201A.As a result, it is possible to more reliably uniformize the inductionplasma.

Controller

The controller 221 serving as a control structure is configured tocontrol the components constituting the substrate processing apparatus100. For example, the controller 221 is configured to control the APCvalve 242, the valve 243B and the vacuum pump 246 via a signal line “A”shown in FIG. 1 . For example, the controller 221 is configured tocontrol the susceptor elevator 268 via a signal line “B” shown in FIG. 1. For example, the controller 221 is configured to control a heaterpower regulator 276 and the variable impedance regulator 275 via asignal line “C” shown in FIG. 1 . For example, the controller 221 isconfigured to control the gate valve 244 via a signal line “D” shown inFIG. 1 . For example, the controller 221 is configured to control the RFsensor 272, the RF power supply 273, the matcher 274, the RF sensor 282,the RF power supply 283 and the matcher 284 via a signal line “E” shownin FIG. 1 . For example, the controller 221 is configured to control theMFCs 252A, 252B and 252C, the valves 253A, 253B and 253C and the valve243A via a signal line “F” shown in FIG. 1 .

As shown in FIG. 10 , the controller 221 (control structure) isconstituted by a computer including a CPU (Central Processing Unit)221A, a RAM (Random Access Memory) 221B, a memory 221C and an I/O port221D. The RAM 221B, the memory 221C and the I/O port 221D may exchangedata with the CPU 221A through an internal bus 221E. For example, aninput/output device 225 constituted by components such as a touch paneland a display may be connected to the controller 221.

For example, the memory 221C is configured by a component such as aflash memory and a hard disk drive (HDD). For example, a control programconfigured to control the operation of the substrate processingapparatus 100 or a process recipe containing information on thesequences and conditions of the substrate processing described later isreadably stored in the memory 221C. The process recipe is obtained bycombining steps of the substrate processing described later such thatthe controller 221 can execute the steps to acquire a predeterminedresult, and functions as a program. Hereinafter, the process recipe andthe control program are collectively or individually referred to as a“program”. Thus, in the present specification, the term “program” mayrefer to the process recipe alone, may refer to the control programalone, or may refer to both of the process recipe and the controlprogram. The RAM 221B functions as a memory area (work area) where aprogram or data read by the CPU 221A is temporarily stored.

The I/O port 221D is electrically connected to the components describedabove such as the MFCs 252A through 252C, the valves 253A through 253C,the valves 243A and 243B, the gate valve 244, the APC valve 242, thevacuum pump 246, the RF sensor 272, the RF power supply 273, the matcher274, the RF sensor 282, the RF power supply 283, the matcher 284, thesusceptor elevator 268, the variable impedance regulator 275 and theheater power regulator 276.

The CPU 221A is configured to read and execute the control programstored in the memory 221C, and to read the process recipe stored in thememory 221C in accordance with an instruction such as an operationcommand inputted via the input/output device 225. The CPU 221A isconfigured to control the operation of the substrate processingapparatus 100 according to the read process recipe. For example, the CPU221A is configured to perform an operation of adjusting an openingdegree of the APC valve 242, an opening and closing operation of thevalve 243B and a start and stop of the vacuum pump 246 via the I/O port221D and the signal line A according to the read process recipe. Forexample, the CPU 221A is configured to perform an elevating and loweringoperation of the susceptor elevator 268 via the signal line B accordingto the read process recipe. For example, the CPU 221A is configured toperform a power supply amount adjusting operation (temperature adjustingoperation) on the heater 217B by the heater power regulator 276 and animpedance adjusting operation by the variable impedance regulator 275via the signal line C according to the read process recipe. For example,the CPU 221A is configured to perform an opening and closing operationof the gate valve 244 via the signal line D according to the readprocess recipe. For example, the CPU 221A is configured to perform acontrolling operation of the RF sensor 272, the matcher 274, the RFpower supply 273, the RF sensor 282, the matcher 284 and the RF powersupply 283 via the signal line E according to the read process recipe.For example, the CPU 221A is configured to perform flow rate adjustingoperations for various gases by the MFCs 252A, 252B and 252C and openingand closing operations of the valves 253A, 253B, 253C and 243A via thesignal line F according to the read process recipe. The CPU 221A maycontrol operations of components of the substrate processing apparatus100 other than the components described above.

The controller 221 may be embodied by installing the above-describedprogram stored in an external memory 226 into a computer. For example,the external memory 226 may include a magnetic tape, a magnetic disksuch as a flexible disk and a hard disk, an optical disk such as a CDand a DVD, a magneto-optical disk such as an MO and a semiconductormemory such as a USB memory and a memory card. The memory 221C or theexternal memory 226 may be embodied by a non-transitory computerreadable recording medium. Hereafter, the memory 221C and the externalmemory 226 are collectively or individually referred to as a “recordingmedium”. In the present specification, the term “recording medium” mayrefer to the memory 221C alone, may refer to the external memory 226alone, and may refer to both of the memory 221C and the external memory226. Instead of the external memory 226, a communication means such asthe Internet and a dedicated line may be used for providing the programto the computer.

(2) Substrate Processing

Subsequently, the substrate processing according to the presentembodiments will be described with reference to FIG. 11 . FIG. 11 is aflowchart schematically illustrating the substrate processing accordingto the present embodiments. For example, the substrate processing, whichis a part of a manufacturing process of a semiconductor device such as aflash memory, is performed by the substrate processing apparatus 100described above. In the following description, the operations of thecomponents constituting the substrate processing apparatus 100 arecontrolled by the controller 221.

For example, although not shown, a trench is formed in advance on thesurface of the wafer 200 to be processed by the substrate processingaccording to the present embodiments. In addition, the trench includes aconcave-convex portion of a high aspect ratio. According to the presentembodiments, for example, the oxidation process serving as a processusing the plasma (that is, the substrate processing) is performed to asilicon layer exposed on an inner wall of the trench.

Substrate Loading Step S110

First, the wafer 200 is transferred (loaded) into the process chamber201. Specifically, the susceptor 217 is lowered to a position fortransferring the wafer 200 (also referred to as a “transfer position”)by the susceptor elevator 268 such that the wafer lift pins 266 passthrough the through-holes 217A of the susceptor 217. As a result, thewafer lift pins 266 protrude from a surface of the susceptor 217 by apredetermined height.

Subsequently, the gate valve 244 is opened, and the wafer 200 istransferred (loaded) into the process chamber 201 using a wafer transferdevice (not shown) from a vacuum transfer chamber (not shown) providedadjacent to the process chamber 201. The wafer 200 loaded into theprocess chamber 201 is placed on and supported in a horizontalorientation by the wafer lift pins 266 protruding from the surface ofthe susceptor 217. After the wafer 200 is loaded into the processchamber 201 and supported by the wafer lift pins 266, the wafer transferdevice is retracted to an outside of the process chamber 201. Then, thegate valve 244 is closed to seal (close) an inside of the processchamber 201 hermetically. Thereafter, by elevating the susceptor 217using the susceptor elevator 268, the wafer 200 is placed on andsupported by an upper surface of the susceptor 217.

Temperature Elevation and Vacuum Exhaust Step S120

Subsequently, a temperature of the wafer 200 loaded into the processchamber 201 is elevated. The heater 217B is heated in advance, and thewafer 200 is held by the susceptor 217 in which the heater 217B isembedded. Thereby, for example, the wafer 200 is heated to apredetermined temperature within a range from 150° C. to 750° C.Further, while the wafer 200 is being heated, the vacuum pump 246vacuum-exhausts the inner atmosphere of the process chamber 201 throughthe gas exhaust pipe 231 such that an inner pressure of the processchamber 201 reaches and is maintained at a predetermined pressure. Thevacuum pump 246 continuously vacuum-exhausts the inner atmosphere of theprocess chamber 201 at least until a substrate unloading step S160described later is completed.

Reactive Gas Supply Step S130

Subsequently, the oxygen-containing gas and the hydrogen-containing gasare supplied into the process chamber 201 as the reactive gas.Specifically, the valves 253A and 253B are opened to start a supply ofthe oxygen-containing gas and a supply of the hydrogen-containing gas,respectively, into the process chamber 201 while flow rates of theoxygen-containing gas and the hydrogen-containing gas are adjusted bythe MFCs 252A and 252B, respectively. In the reactive gas supply stepS130, for example, the flow rate of the oxygen-containing gas is set toa predetermined flow rate within a range from 20 sccm to 2,000 sccm. Inaddition, for example, the flow rate of the hydrogen-containing gas isset to a predetermined flow rate within a range from 20 sccm to 1,000sccm.

In the reactive gas supply step S130, the inner atmosphere of theprocess chamber 201 is exhausted by adjusting the opening degree of theAPC valve 242 such that, for example, the inner pressure of the processchamber 201 is at a predetermined pressure within a range from 1 Pa to250 Pa. The oxygen-containing gas and the hydrogen-containing gas arecontinuously supplied into the process chamber 201 while appropriatelyexhausting the inner atmosphere of the process chamber 201 until aplasma processing step S140 described later is completed.

For example, as the oxygen-containing gas, a gas such as oxygen (O₂)gas, nitrogen peroxide (N2O) gas, nitrogen monoxide (NO) gas, nitrogendioxide (NO2) gas, ozone (O3) gas, water vapor (H2O gas), carbonmonoxide (CO) gas and carbon dioxide (CO2) gas may be used. In addition,one or more of the gases described above may be used as theoxygen-containing gas.

Further, for example, as the hydrogen-containing gas, a gas such ashydrogen (H2) gas, deuterium (D2) gas, the H2O gas and ammonia (NH3) gasmay be used. In addition, one or more of the gases described above maybe used as the hydrogen-containing gas. When the H2O gas is used as theoxygen-containing gas, it is preferable that a gas other than the H2Ogas is used as the hydrogen-containing gas. In addition, when the H2Ogas is used as the hydrogen-containing gas, it is preferable that a gasother than the H2O gas is used as the oxygen-containing gas.

For example, as the inert gas, nitrogen (N2) gas may be used. Inaddition, a rare gas such as argon (Ar) gas, helium (He) gas, neon (Ne)gas and xenon (Xe) gas may be used as the inert gas. For example, one ormore of the gases described above may be used as the inert gas.

Plasma Processing Step S140

In the plasma processing step S140, first, while supplying the processgas through the gas supplier, the RF power is supplied from the RF powersupplier 271 to the first resonance coil 212 without supplying the RFpower from the RF power supplier 281 to the second resonance coil 214.Specifically, when the inner pressure of the process chamber 201 isstabilized, a supply of the RF power is started for the first resonancecoil 212 from the RF power supply 273 via the RF sensor 272.

Thereby, a high frequency electromagnetic field is formed in the plasmageneration space 201A to which the oxygen-containing gas and thehydrogen-containing gas are supplied. As a result, the donut-shaped ICP310 whose plasma density is the highest at a height corresponding to theelectrical midpoint of the first resonance coil 212 in the plasmageneration space 201A is excited by the high frequency electromagneticfield. The oxygen-containing gas and the hydrogen-containing gas areexcited into a plasma state and dissociate. As a result, reactivespecies such as oxygen radicals containing oxygen (oxygen activespecies), oxygen ions, hydrogen radicals containing hydrogen (hydrogenactive species) and hydrogen ions can be generated.

The radicals generated by the induction plasma and non-accelerated ionsare uniformly supplied into the trench of the wafer 200 placed on thesusceptor 217 in the substrate processing space 201B. Then, the radicalsand the ions uniformly supplied into the trench of the wafer 200uniformly react with a layer (for example, the silicon layer) formed ona surface of the inner wall of the trench. Thereby, the layer formed onthe surface of the inner wall of the trench is modified into an oxidelayer (for example, a silicon oxide layer) whose step coverage is good.

After a predetermined process time (for example, 10 seconds to 300seconds) has elapsed, the supply of the RF power from the RF powersupply 273 is stopped.

Subsequently, while supplying the process gas through the gas supplier,the RF power is supplied from the RF power supplier 281 to the secondresonance coil 214 without supplying the RF power from the RF powersupplier 271 to the first resonance coil 212. Specifically, when theinner pressure of the process chamber 201 is stabilized, a supply of theRF power is started for the second resonance coil 214 from the RF powersupply 283 via the RF sensor 282.

Thereby, a high frequency electromagnetic field is formed in the plasmageneration space 201A to which the oxygen-containing gas and thehydrogen-containing gas are supplied. As a result, the donut-shaped ICP312 whose plasma density is the highest at a height corresponding to theelectrical midpoint of the second resonance coil 214 in the plasmageneration space 201A is excited by the high frequency electromagneticfield. The oxygen-containing gas and the hydrogen-containing gas areexcited into the plasma state and dissociate. As a result, the reactivespecies such as the oxygen radicals containing oxygen (the oxygen activespecies), the oxygen ions, the hydrogen radicals containing hydrogen(hydrogen active species) and the hydrogen ions can be generated.

The radicals generated by the induction plasma (that is, thedonut-shaped ICP 312), the radicals generated by the induction plasma(that is, the donut-shaped ICP 310) generated by the first resonancecoil 212 and whose lifetime is extended in the present step andnon-accelerated ions are uniformly supplied into the trench of the wafer200 placed on the susceptor 217 in the substrate processing space 201B.Then, the radicals and the ions uniformly supplied into the trench ofthe wafer 200 uniformly react with the layer (for example, the siliconlayer) formed on the surface of the inner wall of the trench. Thereby,the layer formed on the surface of the inner wall of the trench ismodified into the oxide layer (for example, the silicon oxide layer)whose step coverage is good.

After a predetermined process time (for example, 10 seconds to 300seconds) has elapsed, the supply of the RF power from the RF powersupply 283 is stopped. Thereby, the plasma discharge in the processchamber 201 is stopped.

In addition, the valves 253A and 253B are closed to stop the supply ofthe oxygen-containing gas and the supply of the hydrogen-containing gasinto the process chamber 201. Thereby, the plasma processing step S140is completed.

Vacuum Exhaust Step S150

After the supply of the oxygen-containing gas and the supply of thehydrogen-containing gas are stopped, the inner atmosphere of the processchamber 201 is vacuum-exhausted through the gas exhaust pipe 231.Thereby, the gas such as the oxygen-containing gas, thehydrogen-containing gas and an exhaust gas generated from the reactiontherebetween in the process chamber 201 is exhausted to the outside ofthe process chamber 201. Thereafter, the opening degree of the APC valve242 is adjusted such that the inner pressure of the process chamber 201is adjusted to the same pressure as that of the vacuum transfer chamber(not shown) provided adjacent to the process chamber 201. The vacuumtransfer chamber serves as an unloading destination of the wafer 200.

Substrate Unloading Step S160

After the inner pressure of the process chamber 201 is adjusted to apredetermined pressure, the susceptor 217 is lowered to the transferposition of the wafer 200 until the wafer 200 is supported by the waferlift pins 266. Then, the gate valve 244 is opened, and the wafer 200 istransferred (unloaded) out of the process chamber 201 by using the wafertransfer device (not shown).

Thereby, the substrate processing according to the present embodimentsis completed.

Other Embodiments

While the technique of the present disclosure is described in detail byway of the embodiments described above, the technique of the presentdisclosure is not limited thereto. For example, the embodimentsdescribed above may be appropriately combined.

For example, the above-described embodiments are described by way of anexample in which the second arrangement region SA is provided closer tothe susceptor 217 than the first arrangement region FA in theup-and-down direction of the substrate processing apparatus 100 (thatis, the vertical direction). However, the technique of the presentdisclosure is not limited thereto. For example, the second arrangementregion SA may be provided farther from the susceptor 217 than the firstarrangement region FA in the up-and-down direction of the substrateprocessing apparatus 100 (that is, the vertical direction).

For example, the above-described embodiments are described by way of anexample in which the first arrangement region FA and the secondarrangement region SA are provided on the outer periphery of the processvessel 203 as shown in FIG. 8 . However, the technique of the presentdisclosure is not limited thereto. For example, as shown in FIG. 12 , athird arrangement region TA may be provided opposite to the firstarrangement region FA with the second arrangement region SA providedtherebetween. In the third arrangement region TA, the conductor 212A ofthe first resonance coil 212 and the conductor 214A of the secondresonance coil 214 are alternately arranged in the vertical direction(that is, the axial direction of each resonance coil). In such a case,by grounding the both ends of the first resonance coil 212, it ispossible to provide the multiple of the wavelength of the RF powersupplied to the first resonance coil 212. Thereby, it is possible toprovide the sine curve of the voltage. As a result, it is possible toeasily control the peak of the voltage distribution of the firstresonance coil 212.

For example, the above-described embodiments are described by way of anexample in which the axial length of the coil portion of the firstresonance coil 212 is set to be different from the axial length of thecoil portion of the second resonance coil 214. However, the technique ofthe present disclosure is not limited thereto. For example, the axiallength of the coil portion of the first resonance coil 212 may be thesame as the axial length of the coil portion of the second resonancecoil 214. In such a case, for example, the first resonance coil 212 andthe second resonance coil 214 may be arranged such that the firstresonance coil 212 entirely overlaps with the second resonance coil 214,or such that a lower portion of the first resonance coil 212 overlapswith an upper portion of the second resonance coil 214. Further, evenwhen the axial length of the coil portion of the first resonance coil212 is set to be different from the axial length of the coil portion ofthe second resonance coil 214, the first resonance coil 212 and thesecond resonance coil 214 may be arranged such that a part of the coilportion of the first resonance coil 212 in the axial direction overlapswith a part of the coil portion of the second resonance coil 214 in theaxial direction.

For example, the above-described embodiments are described by way of anexample in which the process chamber 201 defined by the process vessel203 includes the plasma generation room and the substrate processingroom (That is, the plasma generation room and the substrate processingroom are configured by the same process vessel 203). However, thetechnique of the present disclosure is not limited thereto. For example,the plasma generation room and the substrate processing room may beconfigured as separate vessels.

For example, the above-described embodiments are described by way of anexample in which the oxidation process using the plasma is performedonto the surface of the substrate. However, the technique of the presentdisclosure is not limited thereto. For example, a nitridation processusing a nitrogen-containing gas as the process gas may be performed.Further, the technique of the present disclosure is not limited to thenitridation process and the oxidation process, and may be applied toother processing techniques of processing the substrate using theplasma. For example, the technique of the present disclosure may beapplied to a process such as a modification process onto a film formedon the surface of the substrate, a doping process, a reduction processof an oxide film, an etching process with respect to the film and aphotoresist ashing process, which are performed by using the plasma.

For example, the above-described embodiments are described by way of anexample in which the two resonance coils are used. However, thetechnique of the present disclosure is not limited thereto. For example,three or more resonance coils may be used.

For example, the above-described embodiments are described by way of theembodiments and modified examples described above. However, thetechnique of the present disclosure is not limited thereto. It isapparent to the person skilled in the art that the technique of thepresent disclosure may be modified in various ways without departingfrom the scope thereof.

According to some embodiments of the present disclosure, it is possibleto improve the uniformity of the substrate processing on the surface ofthe substrate.

What is claimed is:
 1. A substrate processing apparatus comprising: aprocess chamber comprising: a plasma generation space capable ofgenerating a plasma; and a substrate processing space capable ofprocessing a substrate; a gas supplier capable of supplying a gas intothe plasma generation space; a first coil provided to surround theplasma generation space and configured to generate a first voltagedistribution; and a second coil provided to surround the plasmageneration space and configured to generate a second voltagedistribution such that a peak of the second voltage distribution doesnot overlap with a peak of the first voltage distribution.
 2. Thesubstrate processing apparatus of claim 1, wherein the second coil isfurther configured such that, in a direction perpendicular to an axialdirection, the peak of the second voltage distribution does not overlapwith the peak of the first voltage distribution.
 3. The substrateprocessing apparatus of claim 1, wherein the second coil is furtherconfigured such that, in an axial direction, the peak of the secondvoltage distribution does not overlap with the peak of the first voltagedistribution.
 4. The substrate processing apparatus of claim 1, whereina first arrangement region in which a conductor constituting the firstcoil and a conductor constituting the second coil are alternatelyarranged in the axial direction, and a second arrangement region inwhich the conductor constituting the first coil is arranged and woundeda plurality of times with a gap without arranging the conductorconstituting the second coil in the axial direction are provided at anouter side of the plasma generation space.
 5. The substrate processingapparatus of claim 4, wherein the second arrangement region is providedcloser to a substrate support on which the substrate is placed than thefirst arrangement region in the axial direction.
 6. The substrateprocessing apparatus of claim 5, further comprising an exhauster capableof exhausting the gas from an outer periphery of the substrate support.7. The substrate processing apparatus of claim 4, wherein, in the firstarrangement region, the conductor of the first coil and the conductor ofthe second coil are separated from each other at a distance such that noarc discharge is generated therebetween, and, in the second arrangementregion, the conductor of the first coil is provided such that no arcdischarge is generated between wounded portions of the conductor of thefirst coil.
 8. The substrate processing apparatus of claim 4, whereinthe second arrangement region is provided farther from a substratesupport on which the substrate is placed than the first arrangementregion in the axial direction.
 9. The substrate processing apparatus ofclaim 4, wherein a third arrangement region in which the conductor ofthe first coil and the conductor of the second coil are alternatelyarranged in the axial direction is provided on an outer periphery of theplasma generation space opposite to the first arrangement region withthe second arrangement region provided therebetween.
 10. The substrateprocessing apparatus of claim 1, wherein a winding diameter of the firstcoil is set to be different from a winding diameter of the second coil.11. The substrate processing apparatus of claim 1, wherein a windingdiameter of the first coil is set to be less than a winding diameter ofthe second coil.
 12. The substrate processing apparatus of claim 1,wherein the first coil comprises a pair of ground connection portionscapable of being connected to a ground, and an electrical length betweenthe pair of ground connection portions of the first coil is set to be amultiple of a wavelength of an electric power supplied to the firstcoil.
 13. The substrate processing apparatus of claim 12, wherein thesecond coil comprises a pair of ground connection portions capable ofbeing connected to the ground, and an electrical length between the pairof ground connection portions of the second coil is set to be a multipleof a wavelength of the electric power supplied to the second coil. 14.The substrate processing apparatus of claim 13, wherein a position of aground connection portion among the pair of ground connection portionsof the first coil located adjacent to a first end of the first coil inthe axial direction is set to be different from a position of a groundconnection portion among the pair of ground connection portions of thesecond coil located adjacent to a first end of the second coil in theaxial direction.
 15. The substrate processing apparatus of claim 13,wherein a position of a ground connection portion among the pair ofground connection portions of the first coil located adjacent to asecond end of the first coil in the axial direction is set to bedifferent from a position of a ground connection portion among the pairof ground connection portions of the second coil located adjacent to asecond end of the second coil in the axial direction.
 16. The substrateprocessing apparatus of claim 1, wherein a waveform adjustment circuitconfigured to correct an electrical length is provided at at least oneof the first coil or the second coil such that the electrical length ofthe first coil and the electrical length of the second coil are equal toeach other.
 17. The substrate processing apparatus of claim 1, whereinan axial direction of the first coil is equal to that of the secondcoil.
 18. A substrate processing method, comprising: (a) generating afirst voltage distribution by a first coil provided to surround a plasmageneration space and generating a second voltage distribution by asecond coil provided to surround the plasma generation space, wherein apeak of the second voltage distribution does not overlap with a peak ofthe first voltage distribution; and (b) generating a plasma by supplyinga gas into the plasma generation space of a process chamber providedwith the plasma generation space and a substrate processing space, andprocessing a substrate accommodated in the substrate processing space.19. A method of manufacturing a semiconductor device, comprising thesubstrate processing method of claim
 18. 20. A non-transitorycomputer-readable recording medium storing a program that causes, by acomputer, a substrate processing apparatus to perform: (a) generating afirst voltage distribution by a first coil provided to surround a plasmageneration space and generating a second voltage distribution by asecond coil provided to surround the plasma generation space, wherein apeak of the second voltage distribution does not overlap with a peak ofthe first voltage distribution; and (b) generating a plasma by supplyinga gas into the plasma generation space of a process chamber providedwith the plasma generation space and a substrate processing space, andprocessing a substrate accommodated in the substrate processing space.